Multi-Section Header with Flexible Crop Cutting Knife

ABSTRACT

A crop harvesting header having a frame mounted on a propulsion vehicle has a cutter bar carrying a sickle knife and a draper transport. The draper is guided at its front edge by a longitudinally extending rail mounted on the frame for movement therewith. The cutter bar is mounted on the frame at spaced positions by spring blades attached to a fixed beam at the rear which allow up and down flexing movement of the cutter bar relative to the draper engagement member. At the center discharge the cutter bar is carried on shorter blades which are carried on a beam in front of the front draper roller. The small amount of flexing of the cutter bar combines with a balanced three piece header frame to provide effective ground following.

This invention relates to a crop harvesting header on which is carried aflexible crop cutting knife. The header frame can be formed as amulti-section construction hinged at one or more forwardly extendingpivot points but many of the features of the invention are applicable toheaders where the frame is rigid. The header is of the type which uses adraper arrangement for transferring the cut crop to the dischargeopening. A reel is also typically provided which carries the crop overthe cutting knife.

BACKGROUND OF THE INVENTION

Headers for a crop harvesting machine generally comprises a mainlongitudinal support member in the form of an elongate tube whichextends across substantially the full width of the header frame anddefines a main structural member for the header frame. The tube carriesa plurality of forwardly and downwardly extending support beams whichinclude a first portion extending downwardly and a second portionattached to a lower end of the first portion and extending forwardlytherefrom toward a forward end of the support beams. The cutter bar isattached to the forward end of the support beams and is thus heldthereby in a position generally parallel to the main support tube.

Many headers are of a type in which the cutter bar is intended to be ina fixed rigid position relative to the main support tube so that thecutter bar is not intended to flex or float relative to the mainstructural tube in response to changes in ground contour.

This rigid type of header has the advantage that it allows more accuratecontrol of the position of the fingers or bats of the reel relative tothe cutter bar so as to more accurately control the crop as it is sweptonto the cutter bar and the table rearwardly of the cutter bar. In thisrigid header type, therefore, the support beams extending forwardly fromthe main structural tube are substantially rigid and hold the cutter barin fixed position.

Alternative types of header mount the cutter bar for flexing movementrelative to the main structural support tube. This type of header isused to provide an improved action in following the contour of theground and is advantageous in some circumstances. Thus when cuttingcrops right at the ground it is desirable that the cutter bar of largerheaders, greater than of the order of 20 feet, is somewhat flexible tofollow the ground contour.

Another type of header provides a multi-section arrangement of frame thehinged at one or more forwardly extending pivot points. This type ofheader again is used to allow close floating action of the cutter bar onthe ground surface.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a crop harvestingheader which provides a flexible cutting sickle knife.

According to a one important aspect of the invention there is provided acrop harvesting header comprising;

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the main frame structure on a        propulsion vehicle for up and down movement relative to the        vehicle;    -   wherein the mounting assembly provides a floating action of the        frame relative to the propulsion vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and carrying a sickle knife operable for cutting the crop        as the header is moved forwardly across the ground;    -   a ground engaging structure for engaging the ground so as to        receive lifting forces from the ground at points of the ground        engaging structure which contact the ground tending to lift the        cutter bar;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the frame being divided at least into a first frame portion and        a second separate frame portion with the second connected by a        pivot coupling arranged for pivotal movement of the second        relative to the first about a pivot axis generally parallel to        the forward direction and intersecting the cutter bar so that,        as the second pivots, the cutter bar bends in the area adjacent        the respective pivot axis to accommodate the pivotal movement;    -   the cutter bar being mounted on the first frame portion at        spaced positions along the length of the first frame portion by        mounting components which allow up and down flexing movement of        the cutter bar relative to the first frame portion;    -   the cutter bar being mounted on the second frame portion at        spaced positions along the length of the second frame portion by        mounting components which allow up and down flexing movement of        the cutter bar relative to the second frame portion;    -   the support assembly including a first support arranged to        provide a first lifting force for the first frame portion        leaving some weight applied by the ground engaging structure of        the first frame portion to the ground;    -   the support assembly including a second support arranged to        provide a second lifting force for the second frame portion        leaving some weight applied by the ground engaging structure of        the second frame portion to the ground;    -   the support assembly being arranged to provide floating movement        for each of the first and second frame portions such that, as        the first and second lifting forces vary, the weight applied by        each of the first and second frame portions to the ground is        maintained at least partly balanced.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and carrying a sickle knife operable for cutting the crop        as the header is moved forwardly across the ground;    -   a ground engaging structure for engaging the ground so as to        receive lifting forces from the ground at points of the ground        engaging structure which contact the ground tending to lift the        cutter bar;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the frame being divided at least into a first frame portion and        a second separate frame portion with the second connected by a        pivot coupling arranged for pivotal movement of the second        relative to the first about a pivot axis generally parallel to        the forward direction and intersecting the cutter bar so that,        as the second pivots, the cutter bar bends in the area adjacent        the respective pivot axis to accommodate the pivotal movement;    -   the cutter bar being mounted on the first frame portion at        spaced positions along the length of the first frame portion by        mounting components which allow up and down flexing movement of        the cutter bar relative to the first frame portion;    -   the cutter bar being mounted on the second frame portion at        spaced positions along the length of the second frame portion by        mounting components which allow up and down flexing movement of        the cutter bar relative to the second frame portion;    -   wherein the amount of flexing movement of the cutter bar        relative to the respective one of the first and second frame        portions allowed by the mounting components is less than a total        of six inches;    -   and wherein the pivotal movement of the first frame portion        relative to the second separate frame portion provided by the        pivot coupling is arranged such that an outer end of the first        frame portion remote from the second frame portion moves        vertically by a distance less than a total of 20 inches.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and having a forwardly extending flange carrying a sickle        knife operable for cutting the crop as the header is moved        forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the draper transport system including a longitudinally extending        draper engagement member adjacent the front edge of the draper,        the draper engagement member being fixed to the frame for        movement therewith;    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to a        rigid member of the frame and therefore relative to the draper        engagement member;    -   wherein the cutter bar is mounted immediately forward of the        draper engagement member with a portion of cutter bar underlying        the draper engagement member.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and having a forwardly extending flange carrying a sickle        knife operable for cutting the crop as the header is moved        forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the draper transport system including a longitudinally extending        draper engagement member adjacent the front edge of the draper,        the draper engagement member being fixed to the frame for        movement therewith;    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to a        rigid member of the frame and therefore relative to the draper        engagement member;    -   wherein there is provided a flexible crop deflector plate        extending between the cutter bar and the draper engagement        member, the defector plate having a front edge fixedly attached        to the cutter bar and having a rear edge surface in sliding        contact with a front surface of the draper engagement member.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and having a forwardly extending flange carrying a sickle        knife operable for cutting the crop as the header is moved        forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the draper transport system including a longitudinally extending        draper engagement member adjacent the front edge of the draper,        the draper engagement member being fixed to the frame for        movement therewith:    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to a        rigid member of the frame and therefore relative to the draper        engagement member;    -   wherein the frame is divided at least into a first frame portion        and a second separate frame portion with the second connected by        a pivot coupling arranged for pivotal movement of the second        relative to the first about a pivot axis generally parallel to        the forward direction and intersecting the cutter bar so that,        as the second pivots, the cutter bar bends in the area adjacent        the respective pivot axis to accommodate the pivotal movement        and wherein the draper engagement member includes a hinge at the        pivot axis.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and carrying a sickle knife operable for cutting the crop        as the header is moved forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to the        frame;    -   wherein the mounting components which allow up and down flexing        movement of the cutter bar relative to the frame comprise a        first fixed frame structure fixedly mounted relative to the        frame including a rigid member extending longitudinally of the        frame parallel to and rearwardly of the cutter bar and located        forwardly of a rear bottom member of the frame a rear edge of        the draper and a plurality of support members extending        forwardly from the first rigid member to the cutter bar allowing        the up and down flexing movement of the cutter bar relative to        the rigid member.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and carrying a sickle knife operable for cutting the crop        as the header is moved forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to the        frame;    -   wherein the mounting components which allow up and down flexing        movement of the cutter bar relative to the frame comprise a        plurality of flexible blades each rigidly attached at its rear        end to a rigid member of the frame and rigidly attached at its        forward end to the cutter bar and providing flexibility between        the rear end and forward end.

According to a one important aspect of the invention there is provided acrop harvesting header comprising:

-   -   a frame extending across a width of the header for movement in a        forward direction generally at right angles to the width across        ground including a crop to be harvested;    -   a mounting assembly for carrying the frame on a propulsion        vehicle for up and down movement relative to the vehicle;    -   a cutter bar arranged to move over the ground in a cutting        action and carrying a sickle knife operable for cutting the crop        as the header is moved forwardly across the ground;    -   a draper transport system for moving the cut crop toward a        discharge location of the header including at least one draper        mounted on rollers generally parallel to the forward direction        so that the draper carries the crop transverse to the forward        direction, the draper having a front edge adjacent the cutter        bar and a rear edge adjacent a rear of the frame;    -   the cutter bar being mounted on the frame at spaced positions        along the length of the frame by mounting components which allow        up and down flexing movement of the cutter bar relative to the        frame;    -   wherein there is provided a center section at the discharge        location of the header at which is located a fore and aft draper        for carrying the cut crop rearwardly from the cutter bar to a        discharge opening, the draper including a front draper roller        located at a positon spaced rearwardly of the cutter bar, and        wherein there is provided a rigid support member across the        frame in front of the front draper roller and at least one        member extending forwardly from the rigid support member to the        cutter bar to allow the flexing thereof.

Preferably the mounting assembly provides a floating action of theheader frame relative to the propulsion vehicle which can be providedeither by a spring arrangement or by float cylinders. Typically theheader can also tilt side to side about a forward axis.

Where a multi-second header is used, preferably the weight applied byeach of the first and second frame portions to the ground is maintainedat feast partly balanced by changing the lifting forces applied to boththe first and second frame portions. In this arrangement, the liftingforces applied to both the first and second frame portions are appliedfrom the propulsion vehicle without gauge wheels. In this arrangement,the lifting forces applied to both the first and second frame portionsis varied by balancing the lifting forces applied to both the first andsecond frame portions relative to a total lifting force applied to themain frame structure without sensors detecting contact with the groundor sensors detecting forces applied to both the first and second frameportions.

Preferably the amount of flexing movement of the cutter bar relative tothe frame of the respective one of the first and second frame portionsallowed by the mounting components is less than a total of six inches,preferably less than a total of four inches and more preferably of theorder of a total of two inches. This very low level of flex of thecutter bar relative to frame is supplemented by movement of one framesection relative to the other where the pivotal movement of the firstframe portion relative to the second separate frame portion provided bythe pivot coupling is arranged such that an outer end of the first frameportion remote from the second frame portion moves vertically by adistance less than a total of 20 inches and preferably less than 15inches and more preferably of the order of 12 to 15 inches.

Preferably the mounting components which allow up and down flexingmovement of the cutter bar relative to the first frame portion comprisesa first fixed frame structure fixedly mounted relative to the firstframe portion including a first rigid member extending longitudinally ofthe first frame portion parallel to and rearwardly of the cutter bar andforwardly of a rear edge of the draper and a plurality of supportmembers extending forwardly from the first rigid member to the cutterbar allowing the up and down flexing movement of the cutter bar relativeto the first rigid member.

Preferably the first rigid member comprises a beam at a position spacedforwardly of a rear of the frame so as to leave an open spacetherebetween and at a position spaced approximately midway across thedraper and underneath a return run of the draper.

Preferably the mounting components which allow up and down flexingmovement of the cutter bar relative to the first frame portion comprisesa flexible blade rigidly attached at its rear end to the frame wheretypically the frame and the cutter bar are connected only by a pluralityof flexible blades each rigidly attached at its rear end to the frameand each carrying the cutter bar at its forward end. While flexibleblades or leaf springs or are preferably used as this provides a simplelight weight inexpensive arrangement with resistance to flexing in boththe upward and downward directions, the mounting components can us(c)pivotal arms which pivot about a single axis transverse to the forwarddirection. Where flexible blades are used, of course these do not pivotabout a single axis but instead they flex at various positions alongtheir length depending on the shape and thickness of the blade selected.

The term “blade” as used herein is not intended to limit the structureto a specific cross-sectional shape which is necessarily wider than itis high. It will be appreciated that the blade can be formed by a singleleaf spring member. However it is not necessarily required that a singleleaf is used as a complex multi-leaf construction can be used dependingon the force required both the support the cutter bar and to resistrearward forces on the cutter bar due to impact. The blade is intendedto provide both upward lifting forces and horizontal resistance tocompression in a single component. The blade is intended to provide theup and down floating movement by flexing rather than by pivotal movementabout a specific axis.

In this arrangement typically the second section comprises a centersection at the discharge location of the header at which is located afore and aft draper for carrying the cut crop rearwardly from the cutterbar to a discharge opening, the draper including a front draper rollerlocated at a positon spaced rearwardly of the cutter bar. The centersection is typically connected to a second wing section opposite thefirst section. In this arrangement preferably there is provided a rigidsupport member across the frame in front of the front draper roller andat least one flexible blade extending forwardly from the rigid supportmember to the cutter bar to allow the flexing thereof.

Preferably the flexible blades at the fore and aft draper are shorterthan the flexible blades in the first section and are arranged toprovide a resistance to bending substantially equal to that of theblades in the first section although the arc of movement may bedifferent.

Preferably the cutter bar has a constant level of flexibility along itslength so that the blades are arranged to provide a constant resistanceto flexing.

Preferably the draper is carried on frame so as to be fixed on the frameagainst flexing with the cutter bar. That is the front edge of thedraper is carried on a longitudinally extending support member fixed onthe frame against flexing with the cutter bar with the cutter barcarried on a plurality of forwardly extending support members underneaththe longitudinal support member.

Preferably there is provided a flexible deflector plate extendingbetween the cutter bar and the longitudinal support member, the defectorplate having a front edge attached to the cutter bar and having a rearedge surface in sliding contact with a front surface of the longitudinalsupport member. In this arrangement, the deflector plate includes a wallstanding upwardly from the cutter bar and extending rearwardly to therear edge which may include a turned down flange at the rear edge forcontacting the front surface of the longitudinal support member. Thedeflector plate is typically divided longitudinally into a plurality ofend to end sections with an overlap between each and the next at theends to accommodate the flexing of the cutter bar.

Preferably the end of cutter bar is fixed to a header end plate of theframe which is held against flexing with the cutter bar. However thecutter bar may be flexible along its whole length and may be supportedon flex blades even at the ends. This arrangement can be typically usedwith a center knife drive wo as to reduce the requirement for rigidityat the ends.

In some cases the cutter bar is allowed to flex upwardly and downwardlywithout physical stops to limit the movement and particularly thedownward movement. The upward stop can be provided by the cutter barimpacting the underside of the draper engagement member which contactsand locates the front edge of the draper.

Preferably wherein the draper engagement member at the front edge of thedraper which is typically fixed to the frame includes a component whichengages a top surface of draper at the front edge to make a sealtherewith. Various arrangements for seal have been previously proposedand can be used. As this member remains fixed relative to the draperitself, sealing can be effective.

In some cases it is desirable to provide a physical stop to limitdownward movement of the cutter bar. In this case the physical stop canbe connected between the draper engagement member and the cutter bar sothat the physical stop is independent of the mounting components.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

FIG. 1 is a schematic rear elevational view of a first embodiment of aheader according to the present invention with the combine harvesterwhich acts as a propulsion vehicle, with the associated adapter and thereel being omitted for convenience of illustration.

FIG. 2 is a schematic top plan view of the header of FIG. 1.

FIGS. 3 and 4 are each a cross sectional views respectively along thelines 3-3 and 4-4 of FIG. 1 including the adapter and float system.

FIG. 5 is a cross sectional view of the components of FIG. 3 on anenlarged scale and showing only the cutter bar and front draper support.

FIG. 6 is a cross sectional view of the components of FIG. 5 showing thecutter bar in different float positions.

FIG. 6A is a cross sectional view of the components of FIG. 6 showingsome aspects in greater detail and showing a number of modifications.

FIG. 7 is a cross sectional view of the components of FIG. 4 on anenlarged scale and showing primarily the cutter bar and center drapersupport.

FIG. 7A is a cross sectional view of the components of FIG. 7 showingsome aspects in greater detail and showing a number of modifications.

FIG. 8 is an isometric view of the components at the center section ofthe header at the center draper.

FIG. 9 is an isometric view of the components at the wing section of theheader at the side draper.

FIG. 10 is an isometric view of the components at the center section ofthe header at the center draper with the draper components removed andshowing some further details and some modifications.

FIG. 11 is a further isometric view of the components at the centersection of FIG. 10 on a larger scale.

In the drawings like characters of reference indicate correspondingparts in the different figures.

DETAILED DESCRIPTION

FIGS. 1 and 2 show in rear elevational view and in plan viewrespectively a header 10 carried on an adapter 11 attached to the feederhouse 12 of a combine harvester. In FIG. 1 the adapter is omitted forconvenience of illustration.

The header 10 includes a frame 13 defined by a main rear beam 14 and aplurality of forwardly extending arms 15 which extend downwardly fromthe beam 14 and then forwardly underneath a table 16 which extendsacross the header. At the forward end of the table 16 is provided acutter bar 17. On top of the table 16 is provided a draper transportsystem 18 (not shown in FIGS. 1 and 2) which carries the crop from thecutter bar across the header to a discharge location at the feeder house12. The draper thus include two side drapers extending from respectiveends of the header inwardly toward the feeder house and a center adaptersection 18B which acts to feed the crop from the side drapers 18Arearwardly to the feeder housing.

The header further includes a reel 19 including a beam 19A on which ismounted a plurality of reel bats (not shown) which are carried on thebeam 19A for rotation with the beam around the axis of the beam. Thebeam is carried on reel support arms 19B which extend from the beamrearwardly and upwardly to a support bracket attached to the transversemain beam 14. The reel arms can be raised and lowered by hydrauliccylinders 19D connected between the respective arm and the beam 14.

In the embodiment shown the reel is mounted on four arms 19B includingtwo arms at the ends of the header and two center arms being spacedapart either side of the adapter 11.

The adapter 11 comprises a frame 20 which attaches to the feeder house12 and carries at its lower end a pair of forwardly extending pivotalarms (not shown) which extend forwardly underneath respective ones ofthe frame members 15 of the header. The pivotal arms can pivot upwardlyand downwardly about a respective pivot pins each independently of theother arm. Each arm is supported by a respective spring carried on arespective stub arm attached to the respective arm. Thus the springprovides tension on the stub arm pulling it upwardly around the pinwhich acts to pull up the respective arm and provide a lifting forceunderneath the header at a lifting point partway along the respectiveframe member 15 and underneath the draper 18 and the table 16.

At the center of the adapter is provided a link 26 which extends fromthe frame 20 forwardly to the central bracket 19C of the beam armsupport brackets. The link 26 is provided in the form of a hydrauliccylinder which allows adjustment of the length of the cylinder thuspivoting the header forwardly and rearwardly about the support point ofthe arms on the underside of the header. Thus the attitude of theheader, that is the angle of the table 16 to the horizontal can betilted by operation of the cylinder forming the link 26.

In addition the attitude of the header about an axis extending forwardlyof the direction of movement that is at right angles to the transversebeam 14 is effected by the independent pivotal movement of the armsprovided by the springs which act as a floatation system. In additionthe whole header can float upwardly and downwardly on the springs withthe link 26 pivoting to accommodate the upward and downward movement andthe arms pivoting about the respective pin.

The cutter bar 17 includes a skid plate 16A which is arranged to engagethe ground. Thus upward force is provided from the ground which tends tolift the header taking weight off the support springs. In practice thesprings are adjusted so that the springs act to support the majority ofthe weight of the header leaving a relatively small proportion of theweight to rest on the ground. Thus the header can float upwardly anddownwardly as the ground provides areas of different height with one endof the header being movable upwardly independently of the other end byindependent flexing of the springs. Thus the header tends to follow theground level. In other arrangements the header can be supported onwheels or skids so as to support the cutter bar spaced away from theground.

The header is formed in a number of sections which are independentlypivotal each relative to the next and in which adjustment of the liftingforce provided by the springs is transferred to each of the sectionsproportionally so that each section can float upwardly and downwardlyand each section applies a force to the ground which is proportional tothe total force of the whole header.

Thus the beam 14 is divided into a number of separate pieces 14A, 14Band 14C depending upon the number of sections of the header. In theembodiment shown there are three sections including a center section10A, a first wing section 10B and a second wing section 10C. The centersection 10A is mounted at the adapter so that the arms extend intoengagement with the center section. The wing sections are pivotallyconnected to the center section such that each can pivot upwardly anddownwardly about a respective pivot axis generally parallel to thedirection of movement.

Thus the beam 14 is split into three portions each co-operating with arespective one of the sections 10A, 10B and 10C and defining a main beamtherefor. Each section of the beam 14 includes respective ones of theframe members 15 which support the respective portion of the table.There is a break 14A between the beam sections 14 of the center section10A and one wing section 10B. The end most frame member 15A of the wingsection 10B is arranged at the break. The end frame member 15B of thecenter section 10A is spaced inwardly from the break leaving space for apivot coupling 27 extending from the frame member 15A to the framemember 15B and defining a pivot pin lying on the pivot axis between thewing section 10B and the center section 10A. The hinge at which thepivotal action occurs is provided by a hinge pin 27A, with one pin beinglocated at each end of the center section 10A. The axis of the pinextends in the forward direction so as to intersect the cutter bar 17which is formed in a manner which allows it to flex on the axis of thepin 27A thus avoiding the necessity for a break in the cutter bar.

Thus the two sections 10A and 10B are supported each relative to theother for pivotal movement of the wing section 10B about the axisextending through the pin 27A and through the cutter bar so that thewing section is supported at its inner end on the center section but theouter end can pivot upwardly and downwardly at so that the weight at theoutboard end is unsupported by the center section and causes downward orcounter clockwise pivotal movement of the wing section 10B.

The wing section 10C is mounted in an identical or symmetrical mannerfor pivotal movement about the other end of the center section 10A. Theamount of pivotal movement allowed of the wing section relative to thecenter section about the axis of the pivot pin is maintained at a smallangle generally less than 6 degrees and preferably less than 4 degreesas controlled by suitable mechanical stop members which are provided ata suitable location with the required mechanical strength to support thewing frame section against upward or downward movement beyond the stopmembers. This provides an amount of flex at the outer ends which isarranged such that an outer end of the first frame portion remote fromthe second frame portion moves vertically from an uppermost position toa lowermost position by a total distance less than 20 inches, morepreferably by a distance less than 15 inches and typically in a suitableexample by a distance in the range of 12 to 15 inches.

The outboard weight of the wing section 10B is supported on a linkage 30which communicates that weight from the inner end of the beam 14 of thesection 10B through to the support for the center section 10A at thesprings 24. The linkage is shown and described in full detail in U.S.Pat. No. 6,675,568 and in U.S. Pat. No. 7,918,076 to which reference maybe made or the disclosures of which are incorporated herein byreference.

In general the linkage operates to transfer the outboard weight of thewing section inwardly to the center section and at the same time tobalance the lifting force provided by the springs 24 so that it isproportionally applied to the center section and to the wing section.

Thus in general the header is attached to the combine feeder house 12using the float system described previously that supports the header sothat it can be moved up when a vertical force about 1% to 15% of itsweight is applied to the cutter bar from the ground. The reaction of thefloat linkage that typically supports 85% to 99% of the header weight onthe header is used to balance the weight of the wings.

The system is designed so that if the operator sets the float so thatthe float system supports 99% of the header weight then the remaining 1%will be evenly distributed across the cutter bar. If the operatorchanges the float so that 85% is supported by the combine harvester thenthe remaining 15% would also be evenly distributed across the cutter barwithout the operator making adjustments. Thus, not only is the totallifting force to each sections varied in proportion to the total liftingforce but also that lifting force on each section is balanced across thewidth of section. As the sections are rigid between the ends, thisrequires that the lifting forces be balanced between the ends to ensurethe even distribution across the cutter bar of each section and thus ofall the sections. This provides an arrangement in which the forcerequired to lift the header is the same force at any location along thelength of the cutter bar, whether that location is at the centersection, at a junction between the center section and the wing sectionor at the wing section. This is achieved in this embodiment by thebalancing system which transfers lifting force between the sections withthe forces being balanced by the balance beam.

The support assembly carrying the center section and the wings includesa first support defined by the springs arranged to provide a firstlifting force for the first frame portion leaving some weight applied bythe conventional skid element 16A or ground support of the first frameportion 10A to the ground. The support assembly also includes a secondsupport defined by the balance system to provide a second lifting forcefor the second frame portion 10B leaving some weight applied by the skidelement of the second frame portion to the ground. Symmetrically in atypical three section header the wing section 10C is also carried by thebalance system on that side of the center section.

The support assembly thus is arranged to provide floating movement foreach of the first 10A and second 10B frame portions such that such thatthe first and second lifting forces vary such that the weight applied byeach of the first and second frame portions to the ground is maintainedat least partly balanced. The springs of course provide a floatingaction of the header frame relative to the propulsion vehicle. Theweight applied by each of the first and second frame portions to theground is maintained at least partly balanced by changing the liftingforces applied to both the first and second frame portions by thesprings and the balance system. As the center section and the wings arecarried from the combine feeder house, the lifting forces applied toboth the first and second frame portions are applied from the propulsionvehicle without gauge wheels.

As the system uses a balance arrangement to balance the loads, thelifting forces applied to both the first and second frame portions isvaried by balancing the lifting forces applied to both the first andsecond frame portions relative to a total lifting force applied to themain frame structure without sensors detecting contact with the groundor sensors detecting forces applied to both the first and second frameportions. However the same arrangement can be provided by using sensorsand actuators.

The header frame sections and the reel sections are hinged and supportedso that the reel will stay in approximately the same position relativeto the cutter bar. Thus the balance system balances the lifting forceapplied to the ends of the center section relative to the lifting forcewhich is applied to the outboard weight of the wing section so that thelifting force is even across the width of the header. Thus if a liftingforce is applied by the ground or any other lifting mechanism forexample merely manually lifting the header at a particular locationacross its width, that would cause the header to rise at that point andto fail at other points. The amount of force necessary to lift theheader at that point will be the same as it is at other points and thislifting force can be varied for the total header and proportioned acrossthe width of the header automatically by the balance beams as describedhereinafter.

It will be appreciated that the inboard weight of the wing section istransferred through the pivot 27 to the outboard end of the centersection and that weight is transferred directly to the balance system.Also the outboard weight of the wing section is transferred through thebalance system.

As shown in FIG. 4 in the section 10A at the center discharge,underneath and behind the rear end of the draper 18B is provided a guidesheet or pan 50 which extends from the rear end of the draper 10Arearwardly through a rear positon 59 behind the draper to a rear end 60at the feeder house 12.

The feed draper 10A and the pan or guide sheet 50 are mounted on twoparallel side arms 18C (FIG. 2) which extend to a rear end 60 of the pan59 at which point the arms are pivoted to the feeder house. The frontend of each arm is supported by the header on a cross member extendingbetween the arms 15 at the forward end 50A of the pan 59. The frontroller 24 of the feed draper is mounted between the arms 18C rearward ofthe cutter bar. The rear roller 25 is mounted between the arms 18Crearward of the front roller. The pan 50 is mounted between the arms 18Cand extends from the rear feed draper roller to the front of the feederhouse at the adapter 11. It is necessary for the arms 18C, draper 18Band pan 50 to flex and pivot to accommodate the floating and pivotingaction of the header. The rear roller 25 of the draper 23 is thusmounted on the arms and therefore also the draper 23 flexes and twiststo accommodate such movement.

The pan 50 may comprise a removable cover 50C underneath the feed draperand the pan 50 both of which span the arms and thus define a commonstructure. Thus both the draper and the pan 50 pivot about the mountingat the rear end 60.

The pan 50 has a width substantially equal to the width of the draper 23so that the material discharged from the draper across the full width ofthe draper is carried rearwardly over the sheet to the feeder house. Thefeed draper 18B is wider than the space between the side drapers 18A sothat the feed draper extends underneath the side drapers to carry thecrop therefrom and to reduce the possibility of crop back feedingunderneath the side drapers.

The movement of the crop material to the feeder house is assisted by arotary feed member 70 carried above the pan 50 with a widthsubstantially equal to the width of the pan 50. The rotary feed member70 includes a drum 71 which carries on its outside surface two helicalauger sections 72 arranged at respective ends of the drum and arrangedso that rotation of the drum in a counter clockwise direction so as tocarry the crop material underneath the rotary feed member across the pan50 causes the crop material at the side edges of the sheet to be drawninwardly toward a center of the sheet. At the center of the drum 71 isprovided a plurality of fingers or other projecting members (not shown)which direct the crop material rearwardly to enter the feeder house 17.The rotary feed member is located such that the outside edge of thehelical flights thereof and the outer edge of the fingers thereof lie ina cylinder which is closely positioned to the rear end of the feeddraper 18B. This distance is preferably of the order of 50 mm or lesssince such a small distance reduces the possibility of crop back-feedingunderneath the feed draper 18B and ensures that the crop is strippedfrom the feed draper by the rotary feed member. The rotary feed memberis carried on two side arms which are mounted at their rear end on atransverse shaft. The rear of the header is defined by two rear sheets81 on respective sides of the header which define an opening 83 at therotary feed member so that the rotary feed member projects through theopening to operate in co-operation with the sheet 50 in the area at therear of the header and on top of the sheet 50. In addition the rotaryfeed member is of a size so that it can cooperate with the sheet 50 inproperly feeding the crop material into the feeder house.

In the arrangement particularly described herein, as shown for examplein FIGS. 5, 6 and 6A, the cutter bar 16 is mounted so that, incombination with the flexing of the header frame, the cutter bar itselfcan flex relative to the header frame to better follow the groundcontour.

Thus the cutter bar forms a separate component defined by cutter bar 85from a further component 86 which forms a draper support bar allowingrelative movement between these two components. The cutter bar 85 formsa plate 85A which carries conventional guards 87 and a conventionalsickle bar 88. The guards 87 include a lower component bolted onto theunderside of the plate 85A and may include an upper component not shownor may comprise a conventional pointed guard as shown. A conventionalskid plate 16A is also provided and mounted on the same bolts 89 as theguard 87.

The draper support bar 86 is mounted in fixed position relative to theframe so that it is carried on the frame arms 15 at a forward endthereof. The bar 86 (FIG. 2) extends along the full length of each ofthe wing sections 10B and 10C so that the outer end of the bar 86 iscarried on a fixed endplate 90 fixed to the wing section of the maintube 14 of the frame. In this way the portion of the bar 86 carried byeach of the wing sections is fixed relative to the respective wingsection and the moves therewith. The bar 86 also extends through thecentre section 10A and is carried on the frame members 15 of the centresection. The bar 86 has sufficient stiffness that it is maintained in afixed position relative to the frame and particularly the members 15along the full length of the header. The bar 86 is hinged at 86H at thelocation where the axis of the pin 27A at the hinge 27 passes throughthe bar 86. Alternatively the bar 86 may have sufficient flexibility totake up the relative movement between the sections 10B and 10C relativeto the center section 10A of the header without provision of a specifichinge. In any event, the bar 86 can bend to accommodate the upward anddownward flexing movement of each of the wing sections 10B, 10C relativeto the centre section 10A.

In some cases the end plate 90 can also be arranged to provideflexibility of the cutter bar 85 relative to the support bar 86. That isthe end members also can be formed as flexible components providingflexibility of the cutter bar along its full length. In thisarrangement, the bar 86 is held fixed to the frame but the cutter bar 85can flex. This can be used in a construction in which the sickle bar isdriven from a center knife drive so that rigid mounting of the ends ofthe cutter bar is not required.

As shown in FIG. 5, the bar 86 carries a forward end 91 of the drapercanvas 92 of the side drapers 18A on a support member 93. Thisarrangement is shown in more detail in U.S. Pat. No. 5,459,986, thedisclosure of which is incorporated herein by reference. In this way theforward edge 91 of the draper is held fixed relative to the frame anddoes not move with the cutter bar 85.

As best shown in FIG. 6A, the cutter bar 85 includes the generally flatplate portion 85A to which the guards are mounted in conventionalmanner. At the rear of the plate 85A is a down-turn portion 85B whichextends downwardly at an angle inclined rearwardly. These portionsprovide flexibility for the cutter bar so that it can flex upwardly anddownwardly from a central position shown in FIG. 5. The amount offlexibility is limited so that the total flexibility relative to therespective one of the frame portions allowed by the mounting componentsis less than a total of six inches, preferably less than a total of fourinches and more preferably and typically of the order of two inches.That is, if the frame including the beam 86 is held in fixed positionwithout any pivotal movement of the wing sections, the total amount ofmovement of a centre part of the cutter bar relative to the end plates90 will be in the range stated above and typically a maximum of 2 inchesbetween an uppermost position and a lowermost position. The flexibilityis however such that this flexing movement can occur at any positionacross the width of the cutter bar so that some portions may be raisedand other portions may be lowered depending upon the height of theground at the position which the cutter bar contacts. At the rear of theportion 85B of the cutter bar is provided a rearwardly extendingcomponent 85C in the form of a plurality of longitudinally spaced tangswhich carry the conventional skid plate 16A which forms part of thecutter bar and is arranged to contact the ground in a sliding action asdescribed above. The skid plate is typically formed of a wear resistantplastics material which is suitably attached to the metal bar 85A so asto contact the ground as the cutter bar moves over the ground. It willbe noted that the skid plate in FIG. 6A has a rear edge 16B at the rearof the tangs 85C and that both of these components are locatedunderneath the bottom wall 103 of the draper engagement bar 86. Thislocation of the skid plate underneath the bar 86 occurs due to the veryclose proximity between the cutter bar 85 and the draper bar 86. Thisproximity is obtained by the small amount of movement of the cutter barwhich is less than 4 inches and typically of the order of 2 inches.

That is, when unsupported by the ground, the cutter bar 85 will sag fromthe central height 85X shown in FIG. 5 to the lowered height shown indash line 85Y in FIG. 6 by a distance of the order of 1 to 3 inches, atwhich point the flexibility and support of the cutter bar prevent orinhibit any further sagging under gravity. In this way the cutter barcan sag into a depression in the ground surface. Typically the cutterbar is pushed up by contact with the ground to the raised position shownin FIG. 6 at 85Z and when the support from the ground is removed, thecutter bar will drop by a distance of the maximum allowed movement whichis typically 2 inches as set forth above.

In some cases the bottom position 85Y may be determined by theflexibility of and tension in the cutter bar 85. However as shown inFIGS. 6A and 11 a physical bottom stop may be provided between the bar86 and the cutter bar 85. This comprises a finger 85S mounted by abracket 85U on the front face of the bar 86 which engages into a slot 85v in a bracket 85T carried on the top surface of the cutter bar 85. Thelength of the slot 85V determines the amount of movement and the bottomof the slot determines the bottom stop. A series of such brackets isprovided at spaced positions along the cutter bar.

In addition to this movement of the cutter bar itself relative to theframe, the wing sections, also can flex upwardly and downwardly from acenter aligned position by distance of the order of 5 inches aspreviously discussed making a total movement of the order of 10 inchesbetween the top and bottom positions. The above amount of movement ofthe cutter bar alone by flexing movement of the cutter bar is very smallin comparison with other systems of a comparable nature. However thisvery small flexibility in combination with the flexing of the wings hasbeen found to provide a very effective action of the cutter bar infollowing ground contours.

The cutter bar 85 is not supported from the draper support bar 86 but isinstead carried by a plurality of forwardly extending members 94 mountedon a beam 95. The beam 95 is attached to the frame members 15 so that itis held rigid with the frame portion to which it is attached. As shownin FIG. 2, the beam 95 is attached at its outer end to the end plate 90and then is connected along its length to the individual ones of thelegs 15. This includes the leg 15 of the innermost end of the respectivewing section. In addition a beam portion 96 is provided in the centresection 10A extending from the end leg 15X of the centre section towardthe beam 94 and aligned therewith but spaced outwardly therefrom so asto define an end 96A. The cutter bar 85 is thus supported along most ofits length by the forwardly extending members 94 attached to the beam 95and 96.

However in view of the presence of the centre draper 18B, the beam 95cannot extend through this area and in addition the forwardly extendingmembers 94 are also prevented from supporting the cutter bar in thisarea in view of the presence of the front roller 24 of the centredraper.

The forwardly extending members 94 each comprise a separate spring bladebolted in fixed position and its rear end to the beam 95 by a fastener97. The rear end of the spring blade therefore is fixed at the rear endand cannot pivot relative to the beam at 95 but the blade can flexupwardly and downwardly to accommodate the flexing movement of thecutter bar 85. The amount of flexing movement of the cutter bar 85 istherefore controlled by both the flexibility of the cutter bar itselfand the flex blades 94. The flex blades 94 are typically formed from asingle flat sheet of spring steel with a forward upward turn 98 toengage under the portion 85B of the plate 85A.

In view of the relatively small amount of movement in the flexing of thecutter bar, the spring blades 94 can be relatively short. Thus the beam95 is positioned well in front of the rear sheets 81 of the headerleaving a clear space between the bottom of the header frame and thebeam 95. Thus the beam is positioned well in front of the rear edge 18Dof the draper and typically approximately midway between the front 18Eand rear 18D edges of the draper. The blades 94 thus do not extendbackward to the frame at the sheets 81 and there is no requirement forpivotal movement of the blades or any other spring support for theblades so the construction is very simple and uses a limited amount ofmetal thus reducing weight. The flex blades 94 are wider at the frontand fear to allow effective connection to the cutter bar 85 and thesupport bar 95 than at the middle to allow softer flexing in the middle.The flex blades 94 are fastened at the front and rear by suitablefastening which can include welded and/or bolted components to providerequired strength and replacability as required.

The beam 95 is located under the bottom or return run of the draper 18Abut in view of the simple construction is supported well above any areawhich might engage the ground behind the cutter bar.

The support for the cutter bar 85 is provided solely by the flexibleblades 94 described above and also additional flexible blades 107 in thearea of the centre draper as described below. There is no requirementfor any additional pivotal components as the springs provide both theflexibility for the movement of the cutter bar and also the support ofthe cutter bar. This support includes the up-and-down support againstgravity and also a forward to rearward support necessary to preventbending of the cutter bar rearwardly in the event of impact withobstacles.

As shown in FIG. 6, in the uppermost position 85Z of the flexingmovement of the cutter bar, the plate 85A engages up against lowerportions of the bar 86. The bar 86 includes a top flange 100, two wallportions 101 and 102 converging to an apex 104 at the front and a bottomflange 103 extending rearwardly from the bottom of the wall portion 12.This forms a generally C shaped structure which has sufficient strengthto provide the rigidity required. The shape of the forward end of theblade 94 is arranged such that it butts against the wall portion 102 andthe flange 103 to act as an upper stop.

An optional feature is shown in FIG. 6 where the beam 95 can be rotatedaround an axis 104 by a lever mechanism generally indicated at 105 fromits initial position shown in FIG. 5 to a second position clockwisearound the axis so as to lift the blade 94 upwardly. This movement canbe used to push the cutter bar 85 into its raised position so that thecutter bar is Socked against flexing movement. This operation can beused in a situation where the cutter bar is raised off the ground and isrequired to be held fixed by the header for cutting the crop at a raisedheight. This movement also be used to adjust the upper and lower endpositions of the movement of the cutter bar.

In the centre section shown in FIGS. 7 and 7A, as stated above thepresence of the centre draper 18B interferes with the possibility forthe beam 95 to pass through this area. In this limited area, therefore,an additional support member 106 is provided connection between theframe members 15 of the centre frame section 10A at a position in frontof the front draper roller 24. The beam or support member 106 istherefore fixed relative to the frame of the centre section and isconnected to the centre portion of the cutter bar by additional shorterspring blades 107. These blades are shaped and arranged similarly to theabove described blades 94 and function in the same manner but are of areduced length due to the limitations on the geometry available. In viewof their shorter length, they typically have a reduced spring strengthso that the amount of force applied to the cutter bar in this area isequal approximately to that of the wing sections.

In view of the fact that the cutter bar 85 is flexing upwardly anddownwardly relative to the support bar 86, there is provided a deflectorplate 110, best shown in FIG. 7A, which extends between the cutter bar85 and the front face of the inclined wall 101 of the support bar 86.The deflector plate 110 is formed from a simple sheet of metal or othersuitable material which has a front horizontal flange 112 directlyattached to the top of the plate 85A of the cutter bar so as to be feedthereto for movement there with. An upper sliding flange 115 contactsthe front face of the wall 101 of the support bar 86. The flange 115 isshaped to lie flat against the front surface of the wall 101. The arc ofmovement of the cutter bar shown at 114 in FIG. 6 is shaped to followsubstantially the angle of the wall 101 so that the flange 115 slidesalong the wall 101 with little or no movement forwardly or rearwardlyrelative to the wall 101 at right angles to the direction of movement.The flexing of the cutter bar 85 therefore can be taken up by thesliding action of the flange 115 on the wail 101 with little or nodeformation of the sheet metal plate 110. The plate therefore can befixed at the front flange 112 with no requirement for mounting springsto accommodate larger movements. The requirement for a slight flexing ofthe plate 110 can be taken up simply by a slight deformation of the walljoining the flange 112 to the flange 115. As best shown in FIG. 7A, thewall of the deflector plate 110 is formed by an upstanding wall portion117 and a rearwardly inclined wall portion 118 with the flange 115 atthe top edge of the inclined wall 118. As there is a very short distancebetween the rear edge of the plate 85A and the front face of wall 101,typically less than 4.0 inches, due to the small amount of movement ofthe cutter bar in this design, the deflector does not need to pivot butis instead bolted at its front edge directly to the flat upper face ofthe cutter bar and extends the short distance to its rear edge which cansimply slide over the front surface of wall 101. The deflector plate isformed in sections separated along the length of the cutler bar witheither a slight space between the ends 119 of the sections or a shortoverlap portion. The sections can be of the order of 3 feel in lengthwhich allows the cutter bar to flex while the deflector plate remainsstraight with the required bending action taking place at the joints 119between the two sections. There is no need therefore for an interlockingaction at the ends 119. Also the small degree of movement of the orderof 2 inches between the cutter bar 85 and the support bar 86 allows thestep defined by the deflector plate 110 to be relatively small to avoidany difficulty in the cut crop being carried over the deflector plate tothe draper. In FIG. 5 it is shown that the flange 115 of the deflectorplate is inclined downwardly so as to lie flat against the front surface110.

As an alternative to the stop member previously defined, a series ofstop members 121 can be located on the support bar 86 at spacedpositions along the bar 86 so that the bottom edge of the deflectorplate 110 engages the stop when the bar 85 drops to its lowest allowedposition thus providing a positive stop against further downwardmovement. This stop system which operates on the cutter bar 85 ratherthan on the spring blades 94 prevents the cutter bar 85 from droppingtoo low so that the flexibility provide by the cutter bar 85 and theblades 94 can be relatively soft while preventing the cutter bar fromflexing too much, which can cause bouncing or oscillation to occur.

1. A crop harvesting header comprising: a frame extending across a widthof the header for movement in a forward direction generally at rightangles to the width across ground including a crop to be harvested; amounting assembly for carrying the main frame structure on a propulsionvehicle for up and down movement relative to the vehicle; wherein themounting assembly provides a floating action of the frame relative tothe propulsion vehicle; a cutter bar arranged to move over the ground ina cutting action and carrying a sickle knife operable for cutting thecrop as the header is moved forwardly across the ground; a groundengaging structure for engaging the ground so as to receive liftingforces from the ground at points of the ground engaging structure whichcontact the ground tending to lift the cutter bar; a draper transportsystem for moving the cut crop toward a discharge location of the headerincluding at least one draper mounted on rollers generally parallel tothe forward direction so that the draper carries the crop transverse tothe forward direction the draper having a front edge adjacent the cutterbar and a rear edge adjacent a rear of the frame; the frame beingdivided at least into a first frame portion and a second separate frameportion with the second connected by a pivot coupling arranged forpivotal movement of the second relative to the first about a pivot axisgenerally parallel to the forward direction and intersecting the cutterbar so that, as the second pivots, the cutter bar bends in the areaadjacent the respective pivot axis to accommodate the pivotal movement;the cutter bar being mounted on the first frame portion at spacedpositions along the length of the first frame portion by mountingcomponents which allow up and down flexing movement of the cutter barrelative to the first frame portion; the cutter bar being mounted on thesecond frame portion at spaced positions along the length of the secondframe portion by mounting components which allow up and down flexingmovement of the cutter bar relative to the second frame portion; thesupport assembly including a first support arranged to provide a firstlifting force for the first frame portion leaving some weight applied bythe ground engaging structure of the first frame portion to the ground;the support assembly including a second support arranged to provide asecond lifting force for the second frame portion leaving some weightapplied by the ground engaging structure of the second frame portion tothe ground; the support assembly being arranged to provide floatingmovement for each of the first and second frame portions such that, asthe first and second lifting forces vary, the weight applied by each ofthe first and second frame portions to the ground is maintained at leastpartly balanced.
 2. The crop harvesting header according to claim 1wherein the weight applied by each of the first and second frameportions to the ground is maintained at least partly balanced bychanging the lifting forces applied to both the first and second frameportions.
 3. The crop harvesting header according to claim 2 wherein thelifting forces applied to both the first and second frame portions areapplied from the propulsion vehicle without gauge wheels.
 4. The cropharvesting header according to claim 2 wherein the Sifting forcesapplied to both the first and second frame portions is varied bybalancing the lifting forces applied to both the first and second frameportions relative to a total lifting force applied to the main framestructure without sensors detecting contact with the ground or sensorsdetecting forces applied to both the first and second frame portions. 5.The crop harvesting header according to claim 1 wherein the amount ofsaid flexing movement of the cutter bar relative to the respective oneof the first and second frame portions allowed by said mountingcomponents is less than a total of six inches, preferably less than atotal of four inches and more preferably of the order of a total of twoinches.
 6. The crop harvesting header according to claim 1 wherein thepivotal movement of the first frame portion relative to the second frameportion provided by said pivot coupling is arranged such that an outerend of the first frame portion remote from the second frame portionmoves vertically by a distance less than a total of 20 inches andpreferably less than 15 inches and more preferably of the order of 12 to15 inches.
 7. The crop harvesting header according to claim 1 whereinthe mounting components which allow up and down flexing movement of thecutter bar relative to the first frame portion comprises a plurality ofsupport members extending forwardly from a rigid member to the cutterbar allowing said up and down flexing movement of the cutter barrelative to the rigid member where a forward end of the rigid member isforward of a rear edge of the draper.
 8. The crop harvesting headeraccording to claim 7 wherein the rigid member comprises a beam at aposition spaced forwardly of a rear of the frame so as to leave an openspace therebetween.
 9. The crop harvesting header according to claim 7wherein the forward end of the rigid member is underneath a return runof the draper.
 10. The crop harvesting header according to claim 7wherein the mounting components comprise a flexible blade rigidlyattached at its rear end to the rigid member.
 11. The crop harvestingheader according to claim 10 wherein each of flexible blades is rigidlyattached at its rear end to the rigid member and each is rigidlyattached to the cutter bar at its front end and provides flexibilitybetween the front and rear ends.
 12. The crop harvesting headeraccording to claim 1 wherein there is provided a center section at thedischarge location of the header at which is located a fore and aftdraper for carrying the cut crop rearwardly from the cutter bar to thedischarge opening, the fore and aft draper including a front draperroller located at a positon spaced rearwardly of the cutter bar, andwherein there is provided a rigid support member extending parallel tothe cutter bar in front of the front draper roller and at least oneflexible blade extending forwardly from the rigid support member to thecutter bar to allow said flexing thereof.
 14. The crop harvesting headeraccording to claim 1 wherein the cutter bar has a constant level offlexibility along its length.
 15. The crop harvesting header accordingto claim 1 wherein the cutter bar has a constant cross-section along itslength so that it has no locations of increased stiffness.
 16. The cropharvesting header according to claim 1 wherein the draper is carried onthe frame so as to be fixed on the frame against flexing with the cutterbar.
 17. The crop harvesting header according to claim 1 wherein a frontedge of the draper is carried on a draper engagement member fixed on theframe against flexing with the cutter bar with the cutter bar carried ona plurality of forwardly extending support members underneath the draperengagement member.
 18. A crop harvesting header comprising: a frameextending across a width of the header for movement in a forwarddirection generally at right angles to the width across ground includinga crop to be harvested; a mounting assembly for carrying the frame on apropulsion vehicle for up and down movement relative to the vehicle; acutter bar arranged to move over the ground in a cutting action andcarrying a sickle knife operable for cutting the crop as the header ismoved forwardly across the ground; a ground engaging structure forengaging the ground so as to receive lifting forces from the ground atpoints of the ground engaging structure which contact the ground tendingto lift the cutter bar; a draper transport system for moving the cutcrop toward a discharge location of the header including at least onedraper mounted on rollers generally parallel to the forward direction sothat the draper carries the crop transverse to the forward direction,the draper having a front edge adjacent the cutter bar and a rear edgeadjacent a rear of the frame; the frame being divided at least into afirst frame portion and a second separate frame portion with the secondconnected by a pivot coupling arranged for pivotal movement of thesecond relative to the first about a pivot axis generally parallel tothe forward direction and intersecting the cutter bar so that, as thesecond pivots, the cutter bar bends in the area adjacent the respectivepivot axis to accommodate the pivotal movement; the cutter bar beingmounted on the first frame portion at spaced positions along the lengthof the first frame portion by mounting components which allow up anddown flexing movement of the cutter bar relative to the first frameportion; the cutter bar being mounted on the second frame portion atspaced positions along the length of the second frame portion bymounting components which allow up and down flexing movement of thecutter bar relative to the second frame portion; wherein the amount ofsaid flexing movement of the cutter bar relative to the respective oneof the first and second frame portions allowed by said mountingcomponents is less than a total of six inches; and wherein the pivotalmovement of the first frame portion relative to the second separateframe portion provided by said pivot coupling is arranged such that anouter end of the first frame portion remote from the second frameportion moves vertically by a distance less than a total of 20 inches.19. The crop harvesting header according to claim 18 wherein the amountof said flexing movement of the cutter bar relative to the respectiveone of the first and second frame portions allowed by said mountingcomponents is less than a total of four inches and is preferably of theorder of a total of two inches.
 20. The crop harvesting header accordingto claim 18 wherein the pivotal movement of the first frame portionrelative to the second separate frame portion provided by said pivotcoupling is arranged such that an outer end of the first frame portionremote from the second frame portion moves vertically by a distance lessthan 15 inches and preferably by a distance in the range of 10 to 15inches.